Configure LACP EtherChannel on Cisco Switch

In this lab we will look at the minimum configuration required to build a redundant and high speed link between two Cisco switches.

Configuration

SW1(config)#interface range gigabitEthernet 0/0-1
!
SW1(config-if-range)#channel-protocol ?
  lacp  Prepare interface for LACP protocol
  pagp  Prepare interface for PAgP protocol
SW1(config-if-range)#channel-protocol lacp 
!
SW1(config-if-range)#channel-group ?
  <1-255>  Channel group number
  auto     Enable LACP auto on this interface
!
SW1(config-if-range)#channel-group 1 ?
  mode  Etherchannel Mode of the interface
!
SW1(config-if-range)#channel-group 1 mode ?
  active     Enable LACP unconditionally
  auto       Enable PAgP only if a PAgP device is detected
  desirable  Enable PAgP unconditionally
  on         Enable Etherchannel only
  passive    Enable LACP only if a LACP device is detected
!
SW1(config-if-range)#channel-group 1 mode active 
Creating a port-channel interface Port-channel 1
!
SW2(config)#interface range gigabitEthernet 0/0-1
!
SW2(config-if-range)#channel-protocol lacp 
SW2(config-if-range)#channel-group 1 mode active 

Depending on your requirements you will need to use either active or passive.

Verification

SW1#
*Oct 26 05:08:04.210: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to up
*Oct 26 05:08:04.220: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up
*Oct 26 05:08:07.008: %LINK-3-UPDOWN: Interface Port-channel1, changed state to up
*Oct 26 05:08:08.008: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel1, changed state to up
!
SW1#show etherchannel summary 
Flags:  D - down        P - bundled in port-channel
        I - stand-alone s - suspended
        H - Hot-standby (LACP only)
        R - Layer3      S - Layer2
        U - in use      N - not in use, no aggregation
        f - failed to allocate aggregator

        M - not in use, minimum links not met
        m - not in use, port not aggregated due to minimum links not met
        u - unsuitable for bundling
        w - waiting to be aggregated
        d - default port

        A - formed by Auto LAG


Number of channel-groups in use: 1
Number of aggregators:           1

Group  Port-channel  Protocol    Ports
------+-------------+-----------+-----------------------------------------------
1      Po1(SU)         LACP      Gi0/0(P)    Gi0/1(P)    
!
SW1#show etherchannel detail 
                Channel-group listing: 
                ----------------------

Group: 1 
----------
Group state = L2 
Ports: 2   Maxports = 4
Port-channels: 1 Max Port-channels = 4
Protocol:   LACP
Minimum Links: 0


                Ports in the group:
                -------------------
Port: Gi0/0
------------

Port state    = Up Mstr Assoc In-Bndl 
Channel group = 1           Mode = Active          Gcchange = -
Port-channel  = Po1         GC   =   -             Pseudo port-channel = Po1
Port index    = 0           Load = 0x00            Protocol =   LACP

Flags:  S - Device is sending Slow LACPDUs   F - Device is sending fast LACPDUs.
        A - Device is in active mode.        P - Device is in passive mode.

Local information:
                            LACP port     Admin     Oper    Port        Port
Port      Flags   State     Priority      Key       Key     Number      State
Gi0/0     SA      bndl      32768         0x1       0x1     0x1         0x3D  

Partner's information:

                  LACP port                        Admin  Oper   Port    Port
Port      Flags   Priority  Dev ID          Age    key    Key    Number  State
Gi0/0     SA      32768     0c73.d669.8000   7s    0x0    0x1    0x1     0x3D  

Age of the port in the current state: 0d:00h:04m:35s

Port: Gi0/1
------------

Port state    = Up Mstr Assoc In-Bndl 
Channel group = 1           Mode = Active          Gcchange = -
Port-channel  = Po1         GC   =   -             Pseudo port-channel = Po1
Port index    = 0           Load = 0x00            Protocol =   LACP

Flags:  S - Device is sending Slow LACPDUs   F - Device is sending fast LACPDUs.
        A - Device is in active mode.        P - Device is in passive mode.

Local information:
                            LACP port     Admin     Oper    Port        Port
Port      Flags   State     Priority      Key       Key     Number      State
Gi0/1     SA      bndl      32768         0x1       0x1     0x2         0x3D  

Partner's information:

                  LACP port                        Admin  Oper   Port    Port
Port      Flags   Priority  Dev ID          Age    key    Key    Number  State
Gi0/1     SA      32768     0c73.d669.8000   1s    0x0    0x1    0x2     0x3D  

Age of the port in the current state: 0d:00h:04m:33s

                Port-channels in the group: 
                ---------------------------

Port-channel: Po1    (Primary Aggregator)

------------

Age of the Port-channel   = 0d:00h:07m:17s
Logical slot/port   = 16/0          Number of ports = 2
HotStandBy port = null 
Port state          = Port-channel Ag-Inuse 
Protocol            =   LACP
Port security       = Disabled

Ports in the Port-channel: 

Index   Load   Port     EC state        No of bits
------+------+------+------------------+-----------
  0     00     Gi0/0    Active             0
  0     00     Gi0/1    Active             0

Time since last port bundled:    0d:00h:04m:33s    Gi0/1
!
SW1#show interfaces status
Port      Name               Status       Vlan       Duplex  Speed Type 
Po1                          connected    1          a-full   auto